The invention utilizes the pressure exerted by a column of water to filter sea water via a membrane of a conventional semipermeable type or filters required for the conversion of salt water into sweet water through the effect of reverse osmosis. The height of the well in which the column of water is formed is chosen in such a manner that the actual weight of the salt water exerts sufficient pressure to pass through the semipermeable membrane. A plurality of columns may be set up. The columns are arranged on the undersoil (substratum) and are in communication with the sea via at least one conduit or channel with sufficient gradient for the salt water to flow to the upper inlet of each column. The sweet water emerging from the filters is collected in at least one tank arranged beneath the water columns, from where it is pumped to the surface. The liquid residues from filtering are collected in at least one residue tank, from which they are pumped to the surface. In addition, provision is made for a service passageway in the lower part of the columns, which allows access to the filters or semipermeable membranes for maintenance of the latter.
展开▼